Vaginal Birth After Cesarean (VBAC): 9 Things to Consider

A C-section doesn't automatically mean another one later. Here's the lowdown on VBACs ((Vaginal Birth After Cesarean) to help you decide what's right for you.

Had a C-section once before, but long to experience the vaginal version? You’re certainly not alone in making your decision: According to the Childbirth Connection (a program of the National Partnership for Women and Families), more than one in five U.S. women give birth to their first child by C-section. The good news is that chances are, you may be able to have a Vaginal Birth After Cesarean (VBAC) — in fact, your doctor may even recommend it. The American Academy of Obstetricians and Gynecologists’ (ACOG) 2010 VBAC guidelines encourage doctors to consider attempting VBACs over elective C-sections in more cases.

VBACs and repeat C-sections both pose risks and advantages. According to the National Institutes of Health, the safest way for women who’ve had a prior C-section to deliver a subsequent baby is by way of a successful VBAC — and VBACs are successful 60 to 80 percent of the time, with the rest of babies delivered by C-section. Elective repeat C-sections are slightly riskier than successful VBACs, because moms are at greater risk of infection, blood loss and organ injury. C-sections also become more risky with every subsequent surgery, so your third C-section is more dangerous than your second, which is more dangerous than your first. But the riskiest way to deliver is via emergency C-section after a failed VBAC, which can happen for many reasons — your labor doesn't progress, perhaps, or there is evidence of fetal distress. The problem, of course, is that by trying for the "safest" option — a successful VBAC — you could find yourself in the riskiest situation, which is an emergency C-section.

One of most problematic causes of a failed VBAC is uterine rupture, which is when the scar on your uterus from your previous C-section re-opens during labor, putting you and your baby at serious risk. Fortunately it’s extremely rare: only one in 100 women who attempts a VBAC experiences uterine rupture.

No doubt, it's a lot to think about. But the good news is there are ways to predict fairly well whether a VBAC might be a wise choice for you depending on your medical history, your pregnancy and your physical characteristics. Here are a few key things to consider:

VBACs are not recommended if you have vertical or T-shaped C-section scars. These types of incisions are more likely to result in uterine rupture, so VBACs are generally only a good idea for women who have low-transverse uterine scars — horizontal scars right above the bikini line. (See What Happens When You Have a C-Section.)

VBACs can be an excellent choice if you’ve ever had a vaginal birth. Research suggests that if you’ve already delivered a baby vaginally — even if it was before your C-section — your likelihood of having a safe and successful VBAC is higher than 90 percent.

VBACs are more likely to succeed if your labor starts spontaneously. Inductions don't work that well for VBACs, in part because doctors can't use as many labor-inducing medicines on women who have uterine scars. What’s more, induction ups your risk for uterine rupture. That's not to say that VBAC inductions can't be done, but if you’re laboring on your own, you’re making progress on your own — which bodes very well for VBAC success.

VBAC attempts may be less successful if your last C-section was necessary because of dystocia, an abnormally slow or difficult labor. If you needed a C-section due to an especially slow or stalled labor, you may experience the same problem the next time you try to deliver vaginally. But if you had a C-section because of something unique to your previous pregnancy that isn't affecting your current pregnancy — maybe your baby was breech last time but is head-down this time — then a successful VBAC becomes more likely.

VBACs can be less successful if you’re overweight/obese or if you gained a lot of weight between your pregnancies. A recent study reported that VBAC success was 40 percent lower among women who gained more than 40 pounds during pregnancy compared to women who gained less than that amount. Overweight and obese women who attempt VBACs are also less likely to successfully deliver vaginally in general.

VBACs may be more risky if your baby is large. Recent research has found the chance of VBAC failure is 50 percent higher when babies weigh more than 8 pounds 13 ounces at delivery compared to when they weigh less than 7 pounds 11 ounces. VBACs with large babies may also increase the risk of uterine rupture and perineal tears — which is part of the reason why some doctors don't perform VBACs on women who are more than a week past their due date. That said, just because you had a large baby before doesn’t mean you'll have one this time (especially if you keep your pregnancy weight gain under control).

VBACs can be an option even if you've had two C-sections, assuming both involved low-transverse uterine incisions.

VBACs may be smart if you want to have a lot of kids. If you're pregnant with your second or third child and you know you want more wee ones down the line, a VBAC might be wise because elective C-sections become more dangerous the more you have. Plus, if you have a successful VBAC now, your chance of a successful VBAC in the future goes up, too.

VBACs are more successful the younger you are.A 2007 study reported that compared to women aged 21 to 34, those over 35 were 14 percent more likely to have an unsuccessful VBAC and were 39 percent more likely to experience VBAC-related complications.

Preparing for a VBAC

Despite the advantages of a VBAC (like a shorter hospital stay, lower risk of infection, and lower costs), you have the right to choose a repeat C-section. If you do push for pushing and your doctor agrees, make sure you discuss the use of prostaglandins or other hormones to stimulate labor, along with the use of pain medication. Know that epidurals do not affect the chances for a successful VBAC — in fact, many doctors recommend epidurals early on during labor to eliminate the need for general anesthesia in the event that an emergency C-section becomes necessary (general anesthesia is riskier for pregnant women than an epidural is). Take a childbirth education class even if you've had one before to give yourself the best preparation possible. Finally, if it doesn't work out, try to take it in stride. The happy ending — healthy you, healthy baby — is really all that matters.

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From the What to Expect editorial team and Heidi Murkoff, author of What to Expect When You're Expecting. Health information on this site is based on peer-reviewed medical journals and highly respected health organizations and institutions including ACOG (American College of Obstetricians and Gynecologists), CDC (Centers for Disease Control and Prevention) and AAP (American Academy of Pediatrics), as well as the What to Expect books by Heidi Murkoff.